Measuring your health through Control Pause

Warning. Most people do not have any problems with measuring the CP. However, some people with heart disease, panic attacks, migraine headaches, and few other, exceptionally rare conditions, may experience unpleasant symptoms, which can appear soon after measuring the CP (in 1-5 minutes). If this happens, do not measure your CP for a while. Later, when your breathing will be about 2-3 times lighter and the CP 2-3 times longer, these unpleasant symptoms after the CP test will not appear. Your initial breathing program should focus on reduction of your pulse (or heart rate).
For over 95% of people, it is safe to measure their CP many times per day and observe the effects of stress, meals, exercise, posture, thermoregulation, and many other life-style factors on your CP, breathing, and health. You can easily measure your body oxygen level using the stress-free BHT (breath holding time) test.
Oxygen content in the organism can be found using a simple method: after exhalation, observe, how long the person can pause their breath without stress.” Dr. K. P. Buteyko, "Dr. Buteyko lecture in the Moscow State University on 9 December 1969"

Sit down and rest for 5-7 minutes. Completely relax all your muscles, including the breathing muscles. This relaxation produces natural spontaneous exhalation (breathing out). Pinch your nose closed at the end of this exhalation and count your BHT (breath holding time) in seconds. Keep nose pinched until you experience the first desire to breathe. Practice shows that this first desire appears together with an involuntary push of the diaphragm or swallowing movement in the throat. (Your body warns you, “Enough!”) If you release the nose and start breathing at this time, you can resume your usual breathing pattern (in the same way as you were breathing prior to the test).
Do not extend breath holding too long trying to increase the control pause. You should not gasp for air or open your mouth when you release your nose. The test should be easy and not cause you any stress. This breath holding time test does not interfere with your breathing.
Warning. Some, not all, people with heart disease, migraine headaches, and panic attacks may experience negative symptoms minutes later after this light version of the test. If this happens, they should avoid this test.]
Some western doctors call such a BHT test “a period of no respiratory sensations” because when the time is voluntarily extended there is a stress that increases with each further second of breath holding.

Look at the diagram above: after the test you can comfortably breathe as before the test. If you stop the test and resume breathing at your first desire to breathe, you will be able to breathe as before: no stress, an easy comfortable procedure.
If you hold the breath for too long, the first inhalations will be deeper, as shown here:

What about usual body oxygen numbers, CP norms and CP of sick and healthy people?
“If a person breath-holds after a normal exhalation,
it takes about 40 seconds before breathing commences”
From the textbook “Essentials of exercise physiology”
McArdle W.D., Katch F.I., Katch V.L. (2-nd edition);
Lippincott, Williams and Wilkins, London 2000, p.252.
Doctor Buteyko and his medical colleagues tested hundred of thousands patients and found that the following relationships generally hold true for the body oxygen index:
1-10 s - severely sick, critically and terminally ill patients, usually hospitalized.
10-20 s - sick patients with numerous complaints and, often, on daily medication.
20-40 s - people with poor health, but often without serious organic problems.
40-60 s - good health.
Over 60 s - ideal health, when many modern diseases are virtually impossible.
These results are in agreement with western medical and physiological research articles and studies, which are summarized on these 2 web pages:
CP (body oxygen index) in sick people
CP (body oxygen level) in healthy people
For the first time in the history of medicine, a group of doctors, after studying and curing thousands of patients, suggested the standard for ideal health that provide guarantee from such chronic conditions as cancer, heart disease, diabetes, COPD, arthritis, and many others. The requirement is to have more than 60 s for the body oxygen level. Moreover, Dr. Buteyko developed the Buteyko method, with the intention to make breathing lighter and increase the control pause.
How does this test relate to breathing?
The bigger your breathing, the smaller your body oxygen level. If we accept the international norm of 40 s and your time is 20 s, you breathe for 2 people. If you have 10 s of oxygen in the body, you breathe for 4 people. Hence, if you breathe less, you naturally increase your body oxygen level.
"I said about measurements of breathing: the control pause is done for measurement of breathing. Not breathing retraining, but its measurement. It is started after exhalation. Breathing retraining is another business. The control pause does not train breathing, but measures it. This is not treatment, this is a measurement." Dr. K. P. Buteyko, "Dr. Buteyko lecture in the Moscow State University on 9 December 1969"